Saudi Journal of Gastroenterology

ARTICLES
Year
: 1997  |  Volume : 3  |  Issue : 3  |  Page : 121--124

Pattern of helicobacter pylori sensitivity to various antimicrobial agents


Saleh Mohsin Al Amri1, Rashed Suliman Al Rashed1, Abdelmageed Mohammad Kambal2, Suliman Mohammed Al Humayed1, Iqbal Y Mayet3,  
1 Department of Medicine, College of Medicine & KKUH, P.O. Box 2925, Riyadh 11461, Saudi Arabia
2 Department of Microbiology, College of Medicine & KKUH, P.O. Box 2925, Riyadh 11461, Saudi Arabia
3 Department of Pharmacy, College of Medicine & KKUH, P.O. Box 2925, Riyadh 11461, Saudi Arabia

Correspondence Address:
Saleh Mohsin Al Amri
Associate Professor & Consultant Physician, Gastroenterology Division (59), College of Medicine & KKUH, P.O. Box 2925, Riyadh 11461
Saudi Arabia

Abstract

To evaluate the pattern of Helicobacter pylori ( H. pylori ) susceptibility to different antimicrobial agents, we prospectively studied 45 H. pylori isolates by disc diffusion method. These isolates were obtained from patients aged between 16-75 years, of both sexes who had no prior history of metronidazole ingestion. A total of 45 patients were included, of which 36 were males with a mean age of 42.9 years and nine females with a mean age of 36.4 years, 62% of patients were Saudis. Almost all the H. pylori isolates were susceptible to clarithromycin, penicillin, erythromycin, ampicillin, tetracycline, clindamycin and cephradine. However, 64.4% of the isolates were resistant to metronidazole. No significant difference was found either in susceptibility of isolates from Saudi, non-Saudi or male and female patients.



How to cite this article:
Al Amri SM, Al Rashed RS, Kambal AM, Al Humayed SM, Mayet IY. Pattern of helicobacter pylori sensitivity to various antimicrobial agents.Saudi J Gastroenterol 1997;3:121-124


How to cite this URL:
Al Amri SM, Al Rashed RS, Kambal AM, Al Humayed SM, Mayet IY. Pattern of helicobacter pylori sensitivity to various antimicrobial agents. Saudi J Gastroenterol [serial online] 1997 [cited 2022 Aug 9 ];3:121-124
Available from: https://www.saudijgastro.com/text.asp?1997/3/3/121/33919


Full Text

There are no generally accepted regimens for the treatment of H. pylori infection in patients with duodenal ulcers. However, metronidazole based regimens have been reported to be among the most successful [1],[2] . Several factors influence the success rate of eradication of H. pylori, the most important being patients' compliance and susceptibility of the organism to metronidazole [3],[5] . Furthermore, resistance to metronidazole could be primary or secondary to previous drug exposure [4],[5] .

We have observed in a previous study, high prevalence of metronidazole resistance in isolates of H. pylori from our population [6] . In order to find out the pattern of H. pylori susceptibility to antimicrobial agents in our community, we prospectively studied the in vitro spectrum of susceptibility of H. pylori to several antimicrobial agents. This would help in future planning for the most appropriate regimen suitable for our population.

 Patient and methods



Forty-five consecutive patients seen at King Khalid University Hospital between January 1995 and December 1995 were included in the study, patients were included if (1) aged between 16-75 years of both sexes, (2) had a negative history of previous metronidazole ingestion obtained from patients or medical records and (3) had a positive growth of H. pylori. Patients were excluded if they had severe coagulopathy. Upper gastrointestinal endoscopies were performed and two antral biopsies were obtained from each patient.

Antral biopsy specimens were transferred to the laboratory in 0.85% sterile saline. If direct transfer was not possible they were left at 4°C for a maximum of 5 hours. In the laboratory they were homogenized in a glass grinder and cultured on plates of sheep blood agar (SBA) and modified Skirrow's selective medium (SSM) containing 7% horse blood, cefsolodin, vancomycin, trimethoprim and amphotericin B [7] . The plates were then incubated microaerophilically in an aerobic jar supplied with a BBL campy pak (Becton-Dickenson, Maryland, USA) at 37°C. The plates were examined for growth on third and eighth day.

Morphologically suspected colonies were confirmed as H. pylori by gram negative curved bacilli appearances, positive oxidase and urease reactions, susceptibility to cephalothin (30 ug disc), resistance to nalidixic acid (30 ug disc) and negative hippurate hydrolysis [7] .

Antimicrobial susceptibility testing

The susceptibility of H. pylori to different antimicrobial agents was performed on blood agar plates incubated microaerophilically at 37°C. Using the stokes comparative disc diffusion method, a known sensitive strain of H. pylori was used as a control. Antimicrobial agents with the following disc potency were tested: metronidazole (5 ug), erythromycin (5 ug), clarithromycin (15 ug), gentamycin (10 ug), penicillin (I unit), ampicillin (10 ug), cephradine (5 ug), clindamycin (2 ug) and tetracycline (10 ug). As cephalothin (30 mg disc) usually gave a large zone of inhibition obliterating other antimicrobial zones of inhibition, it was tested on a separate blood agar plate.

Saudi patients were compared to non-Saudis with regard to age, sex and pattern of isolates susceptibility. Furthermore, antimicrobial susceptibility of isolates from males and females were also compared using Chi square and fissure exact test. P value of H. pylori isolates were cultured. Pattern of susceptibility is shown in [Table 1]. The organisms showed a high in vitro resistance to metronidazole (64.4%). On the other hand, all H. Pylori isolates tested proved highly sensitive to clarithromycin, penicillin, erythromycin, ampicillin, tetracyline, clindamycin and cephradine.

[Table 2] compares Saudi and non-Saudi patients regarding age, sex and pattern of H. pylori susceptibility to Metranidazole. H. Pylori isolates from non-Saudi patients demonstrated a higher Metronidazole resistance rate of 70.6% compared to 60.7% in Saudi patients. However, the difference was not statistically significant. Furtheiiuore, H. Pylori isolates from males showed similar resistance pattern to that from female patients-63.9% versus 66.7% (P=0.8) respectively.

 Discussion



This study showed a high prevalence rate of metronidazole resistance among Saudi and non­Saudi patients (64.4%). Although the non-Saudi patients had higher resistance rate (70.6%) compared to Saudis (60.7), the difference was not statistically significant. This rate (64.4%) is higher than that reported from western population (ranging 20-40%), but lower than that reported from Bangladesh and Zaire (90 & 84%) respectively [1],[3],[4],[5] . Although the number of females in this study is much less than males, H. Pylori isolates showed similar pattern of resistance. This is in contrast to the data reported from other studies, which showed higher resistance rate in isolates from female patients [4],[5] . However, our results are in agreement with those of others who showed similar frequency of resistance among H. pylori isolates from males and females [3] . The recognition of metronidazole resistance is important because this drug in combination with tetracycline and bismuth salt is considered among the most effective regimens for H. pylori eradication [4],[5] . Furthermore, it is also known that primary resistance to metronidazole is associated with higher failure rate of H. pylori eradication [4],[5] . This study also demonstrated a high susceptibility of H. pylori isolates to clarithromycin, ampicillin, tetracycline, erythromycin, clindamycin, cephradine and penicillin. Similar results were previously reported [8],[9],[10],[11],[12],[13] .

Susceptibility of H. pylori to various antimicrobials could be performed by disc diffusion technique or determined with Epsilometer E-test. The latter is a quantitative variant of the disc diffusion method, which is used to measure the minimum inhibitory concentration (MIC). E-test was reported to be reliable, simple to perform and useful for testing fastidious slow-growing organisms such as H. Pylori [4],[14] . Furthermore, the effect of inoculum size preincubation and prediffusion have limited effect on E-test [4],[14] . Baker et al compared E-test with agar dilution, broth microdilution and disc diffusion methods. The four tests were used to evaluate the in vitro susceptibility of four antibiotics against gram-positive and negative organisms. He found a correlation of more than 94% among the four tests [14],[15] . Whether this applies to H. pylori or not may need further studies.

Based on the available results, it seems unlikely that regimens using metronidazole will be highly effective in eradicating H. pylori from our patients population. However, two alternative regimens are available. One includes clarithromycin in combination with tetracycline hydrochloride and bismuth salt, in addition to H2 blocker, another includes omeprazole in comibation with Amoxicyllin and Clarithromycin. The efficacy of both regimens had been proven in western population [1],[8],[16],[17],[18] . However, this needs to be confirmed in our community.

In conclusion, this study demonstrated high metronidazole resistance of H. pylori isolates as tested by disc diffusion technique. This result needs to be confirmed, using quantitative methods. Regimens containing metronidazole are best avoided. Trials to test other antimicrobial combinations are recommended.

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